Augmenting BMI and Waist-Height Ratio for Establishing More Efficient Obesity Percentiles among School-going Children

RESEARCH QUESTIONS: 1. Are all the existing methods for estimating the obesity and overweight in school going children in India equally efficient? 2. How to derive more efficient obesity percentiles to determine obesity and overweight status in school-going children aged 7-12 years old? OBJECTIVES: 1. To investigate and analyze the prevalence rate of obesity and overweight children in India, using the established standards. 2. To compare the efficiency among the tools with the expected levels in the Indian population. 3. To establish and demonstrate the higher efficiency of the proposed percentile chart. STUDY DESIGN: A cross-sectional study using a completely randomized design. SETTINGS: Government, private-aided, unaided, and central schools in the Thrissur district of Kerala. PARTICIPANTS: A total of 1500 boys and 1500 girls aged 7-12 years old. RESULTS: BMI percentiles, waist circumference percentiles, and waist to height ratio are the ruling methodologies in establishing the obese and overweight relations in school-going children. Each one suffers from the disadvantage of not considering either one or more of the obesity contributing factors in human growth dynamics, the major being waist circumference and weight. A new methodology for mitigating this defect through considering BMI and waist circumference simultaneously for establishing still efficient percentiles to arrive at obesity and overweight status is detailed here. Age-wise centiles for obesity and overweight status separately for boys and girls aged 7-12 years old were established. Comparative efficiency of this methodology over BMI had shown that this could mitigate the inability of BMI to consider waist circumference. Also, this had the advantage of considering body weight in obesity analysis, which is the major handicap in waist to height ratio. An analysis using a population of 1500 boys and 1500 girls has yielded 3.6% obese and 6.2% overweight samples, which is well within the accepted range for Indian school-going children. CONCLUSION: The percentiles for school-going children based on age and sex were derived by comparing all other accepted standards used for measurement of obesity and overweight status. Hence, augmenting BMI and waist to height ratio is considered to be the most reliable method for establishing obesity percentiles among school-going children.